I would start out with a clear plan of what the company or students want. If it is simply to pass an English test to get a promotion, I would find a corresponding textbook and teach from that. Often, companies have certain requirements that their employees need to pass in order to get a raise or a promotion.
If it is general "business english" then you can pick up any textbook you want and go from there. Ideally, you would want to balance things off with some basics in effective communication as well. Typically, for lower level learners, I start off with some general free talking and then get into the books. I often discuss a lot of the questions with the student and get them speaking a lot more. Then we would jump into some topic-based discussion that is related to what we have just learned. However, if the student is really struggling, I would just continue with the book.
Most of my students can handle themselves fairly well in English. So most of my lessons are centred around discussion, communication and conversation. These students are looking for ways to improve their English and have typically done every test imaginable. So I mainly coach them on their pronunciation and word usage and/or sentence structure.
These higher level classes do have a textbook but often it gets pushed aside if the discussion is going well. If they have certain criteria that they have to improve, I will tailor the class to help them. Sometimes that means helping them improve their presentation skills or proofing some documents and explaining how to make it clearer for the recipient.